She may have had a heart condition and not been aware of it. Or maybe she kept any heart issues private.
The fact the dog didn’t bark doesn’t mean there wasn’t a squirrel in tree.
The fact that neither the coroner nor the coroner’s physician requested to see medical records because they said instead that there was NO DEATH within their jurisdiction..... means there wasn’t a squirrel in the tree, and no doq to bark at it.